1. Field of the Invention
The present invention relates to systems and methods for applying liquids to foliage and, more particularly, to such systems and methods employing liquids under pressure through a nozzle.
2. Description of Related Art
The spraying of crops and other foliage is known to be accomplished with the use of nozzles through which liquid under pressure is forced and directed to the desired target area, typically the leaves. Concentrate sprayers have difficulties owing to impingement and even distribution of spray particles throughout large target areas. Low-volume sprayers offered some promise in the reduction of the use of spray chemicals, but posed problems of drift and consequent potential contamination of crops, animals, and people. Electrostatic sprayers addressed the drift problem but have proved too complicated and impractical for grower use.
In order to optimize application efficiency, systems have been devised for sensing the location of the foliage and controlling the direction of the spray toward the sensed location. Such systems have lessened the amount of chemical required to be sprayed but still did not address the problem of drift, which can amount to 50% loss of sprayed chemical.
The charging of sprayed liquid has been disclosed by Ward (U.S. Pat. No. 3,195,264), Inculet et al. (U.S. Pat. Nos. 4,666,089 and 4,673,132), Burls et al. (U.S. Pat. No. 4,762,274), Lunzer (U.S. Pat. No. 5,080,289), and Wilson et al. (U.S. Pat. No. 5,228,621). A magnetic-field-generating nozzle for atomizing a molten metal stream into a particle spray is taught by Muench et al. (U.S. Pat. No. 4,925,103). The use of a permanent magnet to increase the efficiency of applying paint has been disclosed by Romanov (SU 1212-606-A). In this device the magnet is outside the spray nozzle and does not come into direct contact with the paint. Further, the sprayer components are not inert.